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Stock Options and Warrants - Additional Information (Detail) (USD $)
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6 Months Ended | 12 Months Ended | 121 Months Ended | 6 Months Ended | 12 Months Ended | 6 Months Ended | 12 Months Ended | 6 Months Ended | 12 Months Ended | 0 Months Ended | 3 Months Ended | 6 Months Ended | 3 Months Ended | 6 Months Ended | 12 Months Ended | 6 Months Ended | 12 Months Ended | 6 Months Ended | 12 Months Ended | 6 Months Ended | 12 Months Ended | 12 Months Ended | 6 Months Ended | 12 Months Ended | |||||||||||||||||||||||
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Nov. 30, 2013
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Nov. 30, 2012
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May 31, 2013
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May 31, 2012
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Nov. 30, 2013
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Nov. 30, 2013
Minimum
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May 31, 2013
Minimum
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May 31, 2012
Minimum
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Nov. 30, 2013
Maximum
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May 31, 2013
Maximum
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May 31, 2012
Maximum
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Nov. 30, 2013
Common Stock Warrants
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Nov. 30, 2013
Holders of Notes
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May 31, 2013
Investor
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Oct. 23, 2013
Private Equity Offering
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Nov. 30, 2013
Private Equity Offering
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Nov. 30, 2013
Private Equity Offering
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Nov. 30, 2013
Private Equity Offering
After amendment
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Nov. 30, 2013
Stock Options
Consultant
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Nov. 30, 2013
2012 Equity Incentive Plan
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Nov. 30, 2012
2012 Equity Incentive Plan
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Nov. 30, 2013
2012 Equity Incentive Plan
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Nov. 30, 2012
2012 Equity Incentive Plan
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May 31, 2013
2012 Equity Incentive Plan
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May 31, 2012
2012 Equity Incentive Plan
|
Nov. 30, 2013
2012 Equity Incentive Plan
Stock Options
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May 31, 2013
2012 Equity Incentive Plan
Stock Options
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Nov. 30, 2013
2012 Equity Incentive Plan
Stock Options
Director
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May 31, 2013
2012 Equity Incentive Plan
Stock Options
Director
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Nov. 30, 2013
2012 Equity Incentive Plan
Stock Options
Director
Minimum
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May 31, 2013
2012 Equity Incentive Plan
Stock Options
Director
Minimum
|
Nov. 30, 2013
2012 Equity Incentive Plan
Stock Options
Director
Maximum
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May 31, 2013
2012 Equity Incentive Plan
Stock Options
Director
Maximum
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May 31, 2013
2012 Equity Incentive Plan
Stock Options
Employees
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May 31, 2013
2012 Equity Incentive Plan
Stock Options
Employees
October 2013
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Oct. 31, 2013
2012 Equity Incentive Plan
Stock Options
Employees
October 2013
Options Expected To Vest
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May 31, 2013
2012 Equity Incentive Plan
Stock Options
Employees
Minimum
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May 31, 2013
2012 Equity Incentive Plan
Stock Options
Employees
Maximum
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Nov. 30, 2013
2012 Equity Incentive Plan
Stock Options 2
Director
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May 31, 2013
2012 Equity Incentive Plan
Stock Options 2
Director
Maximum
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May 31, 2013
2012 Equity Incentive Plan
Stock Options 2
Employees
Minimum
October 2013
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May 31, 2013
2012 Equity Incentive Plan
Stock Options 2
Employees
Maximum
October 2013
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May 31, 2013
2012 Equity Incentive Plan
Warrant
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May 31, 2012
2012 Equity Incentive Plan
Warrant
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May 31, 2013
2012 Equity Incentive Plan
Warrant
Consultant
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May 31, 2013
2012 Equity Incentive Plan
Warrant
Consultant
Minimum
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May 31, 2013
2012 Equity Incentive Plan
Warrant
Consultant
Maximum
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| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] | |||||||||||||||||||||||||||||||||||||||||||||||
| Authorized shares that can be purchased for options and warrants issued | 7,600,000 | 7,600,000 | 7,600,000 | ||||||||||||||||||||||||||||||||||||||||||||
| Shares available for future issuance | 3,000,000 | 3,000,000 | |||||||||||||||||||||||||||||||||||||||||||||
| Shares available for future stock option grants | 1,742,874 | 1,976,710 | |||||||||||||||||||||||||||||||||||||||||||||
| Stock options , shares granted | 17,848,540 | 11,166,274 | 3,456,088 | 305,000 | 233,836 | 148,290 | 1,225,000 | ||||||||||||||||||||||||||||||||||||||||
| Stock options granted, exercise price | $ 0.74 | $ 1.61 | $ 2.04 | $ 0.75 | $ 0.80 | $ 1.40 | $ 0.99 | $ 1.55 | $ 0.80 | $ 1.80 | |||||||||||||||||||||||||||||||||||||
| Expiration date of stock option | 3 years | 1 year | 1 year | ||||||||||||||||||||||||||||||||||||||||||||
| Expiration date of stock option | 1 year | 1 year | 4 years | 4 years | 5 years | 3 years | 5 years | ||||||||||||||||||||||||||||||||||||||||
| Grant date fair value of options | $ 0.43 | $ 0.48 | $ 0.89 | $ 0.60 | |||||||||||||||||||||||||||||||||||||||||||
| Options vesting date | 2013-10 | ||||||||||||||||||||||||||||||||||||||||||||||
| Number of options expected to vest | 112,500 | 112,500 | |||||||||||||||||||||||||||||||||||||||||||||
| Shares against which warrants granted to consultants | 750,000 | 515,000 | |||||||||||||||||||||||||||||||||||||||||||||
| Exercisable warrants, exercise price | 0.75 | 0.75 | 0.50 | 0.75 | 0.75 | 0.75 | 0.75 | 1.00 | 5.00 | ||||||||||||||||||||||||||||||||||||||
| Warrants latest vesting date | Apr. 30, 2013 | ||||||||||||||||||||||||||||||||||||||||||||||
| Warrants expiration dates | 2014-09 | 2015-10 | |||||||||||||||||||||||||||||||||||||||||||||
| Fair value of warrants | $ 0.72 | $ 1.03 | $ 0.56 | ||||||||||||||||||||||||||||||||||||||||||||
| Exercise price | $ 1.30 | $ 1.30 | $ 0.25 | ||||||||||||||||||||||||||||||||||||||||||||
| Compensation expense associated with warrants | $ 1,128,000 | $ 261,000 | $ 487,000 | $ 742,000 | $ 2,354,000 | $ 3,262,000 | $ 1,692,000 | $ 540,000 | |||||||||||||||||||||||||||||||||||||||
| Warrants to purchase common shares, shares | 1 | 8,527,984 | |||||||||||||||||||||||||||||||||||||||||||||
| Net cash proceeds from exercise of common stock warrants | 50,000 | 192,500 | 606,250 | 201,000 | |||||||||||||||||||||||||||||||||||||||||||
| Grant date fair value of options and warrants vested | 8,889,000 | 1,562,000 | |||||||||||||||||||||||||||||||||||||||||||||
| Unrecognized compensation costs | 1,506,000 | 1,506,000 | 1,748,000 | ||||||||||||||||||||||||||||||||||||||||||||
| Weighted average period over which unrecognized compensation costs is expected to be recognized | 2 years 1 month 2 days | 1 year 6 months 26 days | |||||||||||||||||||||||||||||||||||||||||||||
| Percentage of option awards vest at per quarter | 25.00% | ||||||||||||||||||||||||||||||||||||||||||||||
| Warrants exercisable period | 5 years | ||||||||||||||||||||||||||||||||||||||||||||||
| Number of warrants issued | 923,072 | ||||||||||||||||||||||||||||||||||||||||||||||
| Warrants attached with convertible promissory notes | 1,200,000 | ||||||||||||||||||||||||||||||||||||||||||||||
| Number of shares issued | 2 | 2 | 20,989,494 | 2 | |||||||||||||||||||||||||||||||||||||||||||
| Exercisable warrants, expire period | 5 years | 5 years | 7 years | ||||||||||||||||||||||||||||||||||||||||||||
| Stock options, termination date | Sep. 04, 2018 | ||||||||||||||||||||||||||||||||||||||||||||||
| Stock options, number of shares vested on date of issuance | 50,000 | ||||||||||||||||||||||||||||||||||||||||||||||
| Stock options, number of shares vested monthly after initial issuance | 15,000 | ||||||||||||||||||||||||||||||||||||||||||||||
| Consulting agreement term | 6 months | 18 months | |||||||||||||||||||||||||||||||||||||||||||||
| Stock warrants exercised | 50,000 | ||||||||||||||||||||||||||||||||||||||||||||||
| Warrants exercise price per share | $ 1.00 | ||||||||||||||||||||||||||||||||||||||||||||||
| Number of common stock warrants issued | 11,153,850 | 11,153,850 | 4,940,092 | ||||||||||||||||||||||||||||||||||||||||||||
| Proceeds from units sold at private equity offering | 14,500,000 | 14,500,000 | |||||||||||||||||||||||||||||||||||||||||||||
| Purchase Price of warrant | 1.30 | 1.30 | |||||||||||||||||||||||||||||||||||||||||||||
| Warrant to purchase common share | 1 | 1 | 1 | ||||||||||||||||||||||||||||||||||||||||||||
| Grant date fair value of options | 459,000 | 1,574,000 | 6,433,000 | 8,525,000 | |||||||||||||||||||||||||||||||||||||||||||
| Grant date fair value of warrants vested | $ 459,000 | $ 1,574,000 | $ 6,433,000 | $ 8,525,000 | |||||||||||||||||||||||||||||||||||||||||||